The Biomechanics Laboratory continues to develop and test techniques designed to explore the complex relationship between impairments of the neuromusculo-skeletal system, functional limitations, and disability. One study of 18 normal subjects investigated the effect of dramatically different walking speeds on the mechanics of walking. It was demonstrated that, through the use of mechanical power analysis, two modes of walking may exist rather than a continuum of a single walking strategy. Another study evaluated a new technique for determining the role played by each major muscle group of the lower extremity in providing support to and propulsion of the body during walking. The results indicate that forward progression was produced primarily by the ankle plantar flexors, with a significant assist from the knee extensors. The results of these studies suggest that a complete and numerically consistent mechanical characterization of human movement is feasible. The application of these analytic techniques to the evaluation of human motion has implications for rehabilitation and surgical treatment in patient populations.